Antenatal and Postnatal Screening Flashcards
What is the purpose of Antenal Screening?
Antenatal screening identifies the risk of a disorder so that further tests and a prenatal diagnosis can be offered.
What is the purpose of an ultrasound scan.
Ultrasound imaging Pregnant women are given two ultrasound scans. Dating scans which determine pregnancy stage and due date are used with tests for marker chemicals which vary normally during pregnancy.
When does a dating scan take place?
A dating scan takes place between 8 and 14
What do anomaly scans show?
Anomaly scans may detect serious physical abnormalities in the fetus.
When do anomaly scans take place?
An anomaly scan between 18 and 20 weeks.
What are blood and urine tests for?
Routine blood and urine tests are carried out throughout pregnancy to monitor the concentrations of marker chemicals.
What are the names of the diagnostic tests that may be given?
Amniocentesis and chorionic villus sampling (CVS)
Give an advantage and a disadvantage of Chorionic villus sampling over amnioscentisis
CVS can be carried out earlier in pregnancy than amniocentesis, although it has a higher risk of miscarriage.
What happens to samples obtained from CVS and amnioscentisis?
Cells from samples can be cultured to obtain sufficient cells to produce a karyotype to diagnose a range of conditions.
What is a karyotype?
A karyotype shows an individual’s chromosomes arranged as homologous pairs.
Give an example of postnatal screening>
Diagnostic testing for phenylketonuria (PKU). In PKU a substitution mutation means that the enzyme which converts phenylalanine to tyrosine is non-functional.
